adriangb commented on code in PR #15057: URL: https://github.com/apache/datafusion/pull/15057#discussion_r2188925012
########## datafusion-examples/examples/variant_shredding.rs: ########## @@ -0,0 +1,398 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::any::Any; +use std::sync::Arc; + +use arrow::array::{RecordBatch, StringArray}; +use arrow::datatypes::{DataType, Field, Schema, SchemaRef}; +use async_trait::async_trait; + +use datafusion::assert_batches_eq; +use datafusion::catalog::memory::DataSourceExec; +use datafusion::catalog::{Session, TableProvider}; +use datafusion::common::tree_node::{Transformed, TreeNodeRecursion}; +use datafusion::common::{assert_contains, DFSchema, Result}; +use datafusion::datasource::listing::PartitionedFile; +use datafusion::datasource::physical_plan::{FileScanConfigBuilder, ParquetSource}; +use datafusion::execution::context::SessionContext; +use datafusion::execution::object_store::ObjectStoreUrl; +use datafusion::logical_expr::utils::conjunction; +use datafusion::logical_expr::{ + ColumnarValue, Expr, ScalarFunctionArgs, ScalarUDF, ScalarUDFImpl, Signature, + TableProviderFilterPushDown, TableType, Volatility, +}; +use datafusion::parquet::arrow::ArrowWriter; +use datafusion::parquet::file::properties::WriterProperties; +use datafusion::physical_expr::schema_rewriter::PhysicalExprSchemaRewriteHook; +use datafusion::physical_expr::PhysicalExpr; +use datafusion::physical_expr::{expressions, ScalarFunctionExpr}; +use datafusion::physical_plan::ExecutionPlan; +use datafusion::prelude::{lit, SessionConfig}; +use datafusion::scalar::ScalarValue; +use futures::StreamExt; +use object_store::memory::InMemory; +use object_store::path::Path; +use object_store::{ObjectStore, PutPayload}; + +// Example showing how to implement custom filter rewriting for variant shredding. +// +// In this example, we have a table with flat columns using underscore prefixes: +// data: "...", _data.name: "..." Review Comment: Well as we've now found out in that issue the limitation is actually on DataFusion's side. I think what we need for struct fields specifically is for ParquetOpener to generate the right ProjectionMask based on the expressions having a `get_field(col, 'a')` call. So we'd have: 1) SQL: `where name = 'Adrian' and get_field(details, 'coins') > 5` 2) Predicate in Parquet: BinaryExpr(BinaryExpr(Col(0), Eq, lit('Adrian'), And, BinaryExpr(get_field(Col(1), 'coins'), Gt, lit(5)))` 3) Rewrite predicate to BinaryExpr(BinaryExpr(Col(0), Eq, lit('Adrian'), And, BinaryExpr(Col(1), Gt, lit(5)))` and make the projection mask `ProjectionMask::leaves(vec![0, 2])` or something like that instead of `ProjectionMask::roots`: https://github.com/apache/datafusion/blob/12c40ca9499d23a3459c5f9f7712e9f62b3443a1/datafusion/datasource-parquet/src/row_filter.rs#L126-L129 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
